ffmpeg/libavformat/ogg.c

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/*
* Ogg bitstream support
* Mark Hills <mark@pogo.org.uk>
*
* Uses libogg, but requires libvorbisenc to construct correct headers
* when containing Vorbis stream -- currently the only format supported
*/
#include <stdio.h>
#include <ogg/ogg.h>
#include "avformat.h"
#undef NDEBUG
#include <assert.h>
#define DECODER_BUFFER_SIZE 4096
typedef struct OggContext {
/* output */
ogg_stream_state os ;
int header_handled ;
ogg_packet op;
/* input */
ogg_sync_state oy ;
} OggContext ;
#ifdef CONFIG_ENCODERS
static int ogg_write_header(AVFormatContext *avfcontext)
{
OggContext *context = avfcontext->priv_data;
ogg_packet *op= &context->op;
int n, i;
av_set_pts_info(avfcontext, 60, 1, AV_TIME_BASE);
ogg_stream_init(&context->os, 31415);
for(n = 0 ; n < avfcontext->nb_streams ; n++) {
AVCodecContext *codec = &avfcontext->streams[n]->codec;
uint8_t *p= codec->extradata;
for(i=0; i < codec->extradata_size; i+= op->bytes){
op->bytes = p[i++]<<8;
op->bytes+= p[i++];
op->packet= &p[i];
op->b_o_s= op->packetno==0;
ogg_stream_packetin(&context->os, op);
op->packetno++; //FIXME multiple streams
}
context->header_handled = 0 ;
}
return 0 ;
}
static int ogg_write_packet(AVFormatContext *avfcontext,
int stream_index,
const uint8_t *buf, int size, int64_t pts)
{
OggContext *context = avfcontext->priv_data ;
AVCodecContext *avctx= &avfcontext->streams[stream_index]->codec;
ogg_packet *op= &context->op;
ogg_page og ;
pts= av_rescale(pts, avctx->sample_rate, AV_TIME_BASE);
// av_log(avfcontext, AV_LOG_DEBUG, "M%d\n", size);
/* flush header packets so audio starts on a new page */
if(!context->header_handled) {
while(ogg_stream_flush(&context->os, &og)) {
put_buffer(&avfcontext->pb, og.header, og.header_len) ;
put_buffer(&avfcontext->pb, og.body, og.body_len) ;
put_flush_packet(&avfcontext->pb);
}
context->header_handled = 1 ;
}
op->packet = (uint8_t*) buf;
op->bytes = size;
op->b_o_s = op->packetno == 0;
op->granulepos= pts;
/* correct the fields in the packet -- essential for streaming */
ogg_stream_packetin(&context->os, op);
while(ogg_stream_pageout(&context->os, &og)) {
put_buffer(&avfcontext->pb, og.header, og.header_len);
put_buffer(&avfcontext->pb, og.body, og.body_len);
put_flush_packet(&avfcontext->pb);
}
op->packetno++;
return 0;
}
static int ogg_write_trailer(AVFormatContext *avfcontext) {
OggContext *context = avfcontext->priv_data ;
ogg_page og ;
while(ogg_stream_flush(&context->os, &og)) {
put_buffer(&avfcontext->pb, og.header, og.header_len) ;
put_buffer(&avfcontext->pb, og.body, og.body_len) ;
put_flush_packet(&avfcontext->pb);
}
ogg_stream_clear(&context->os) ;
return 0 ;
}
static AVOutputFormat ogg_oformat = {
"ogg",
"Ogg Vorbis",
"audio/x-vorbis",
"ogg",
sizeof(OggContext),
CODEC_ID_VORBIS,
0,
ogg_write_header,
ogg_write_packet,
ogg_write_trailer,
} ;
#endif //CONFIG_ENCODERS
static int next_packet(AVFormatContext *avfcontext, ogg_packet *op) {
OggContext *context = avfcontext->priv_data ;
ogg_page og ;
char *buf ;
while(ogg_stream_packetout(&context->os, op) != 1) {
/* while no pages are available, read in more data to the sync */
while(ogg_sync_pageout(&context->oy, &og) != 1) {
buf = ogg_sync_buffer(&context->oy, DECODER_BUFFER_SIZE) ;
if(get_buffer(&avfcontext->pb, buf, DECODER_BUFFER_SIZE) <= 0)
return 1 ;
ogg_sync_wrote(&context->oy, DECODER_BUFFER_SIZE) ;
}
/* got a page. Feed it into the stream and get the packet */
if(ogg_stream_pagein(&context->os, &og) != 0)
return 1 ;
}
return 0 ;
}
static int ogg_read_header(AVFormatContext *avfcontext, AVFormatParameters *ap)
{
OggContext *context = avfcontext->priv_data;
ogg_packet op ;
char *buf ;
ogg_page og ;
AVStream *ast ;
AVCodecContext *codec;
uint8_t *p;
int i;
avfcontext->ctx_flags |= AVFMTCTX_NOHEADER;
ogg_sync_init(&context->oy) ;
buf = ogg_sync_buffer(&context->oy, DECODER_BUFFER_SIZE) ;
if(get_buffer(&avfcontext->pb, buf, DECODER_BUFFER_SIZE) <= 0)
return -EIO ;
ogg_sync_wrote(&context->oy, DECODER_BUFFER_SIZE) ;
ogg_sync_pageout(&context->oy, &og) ;
ogg_stream_init(&context->os, ogg_page_serialno(&og)) ;
ogg_stream_pagein(&context->os, &og) ;
/* currently only one vorbis stream supported */
ast = av_new_stream(avfcontext, 0) ;
if(!ast)
return AVERROR_NOMEM ;
codec= &ast->codec;
codec->codec_type = CODEC_TYPE_AUDIO;
codec->codec_id = CODEC_ID_VORBIS;
for(i=0; i<3; i++){
if(next_packet(avfcontext, &op)){
return -1;
}
codec->extradata_size+= 2 + op.bytes;
codec->extradata= av_realloc(codec->extradata, codec->extradata_size);
p= codec->extradata + codec->extradata_size - 2 - op.bytes;
*(p++)= op.bytes>>8;
*(p++)= op.bytes&0xFF;
memcpy(p, op.packet, op.bytes);
}
return 0 ;
}
static int ogg_read_packet(AVFormatContext *avfcontext, AVPacket *pkt) {
ogg_packet op ;
if(next_packet(avfcontext, &op))
return -EIO ;
if(av_new_packet(pkt, op.bytes) < 0)
return -EIO ;
pkt->stream_index = 0 ;
memcpy(pkt->data, op.packet, op.bytes);
return op.bytes;
}
static int ogg_read_close(AVFormatContext *avfcontext) {
OggContext *context = avfcontext->priv_data ;
ogg_stream_clear(&context->os) ;
ogg_sync_clear(&context->oy) ;
av_freep(&avfcontext->streams[0]->codec.extradata);
return 0 ;
}
static AVInputFormat ogg_iformat = {
"ogg",
"Ogg Vorbis",
sizeof(OggContext),
NULL,
ogg_read_header,
ogg_read_packet,
ogg_read_close,
.extensions = "ogg",
} ;
int ogg_init(void) {
#ifdef CONFIG_ENCODERS
av_register_output_format(&ogg_oformat) ;
#endif
av_register_input_format(&ogg_iformat);
return 0 ;
}